1. Field of the Invention
The invention relates to computer controlled scanning radar systems, and more particularly, to those utilized for mapping a building or other structure in three dimensions in order to capture "as built" information.
2. Description of Related Art
Once a house, building or other structure has been constructed, the plans, architectural blueprints and engineering specifications are put into storage at some location. This location may be unknown to the building's owners. Even if the location of these documents is known, they may be difficult to retrieve or they may have been destroyed. Additionally these documents may contain significant deviations from the building "as built".
If the original documents are available, but are not in a digital format, or are in a format no longer supported by existing software systems, the architect or engineer is faced with a labor and time intensive effort to enter the data manually. An architect, engineer, builder or owner would certainly prefer to avoid a costly and error-prone data entry process and generate, directly from the building, a three dimensional model of the structure as it currently exists.
Radar systems, such as micropower impulse radar (MIR), are known that rapidly emit radio pulses (approximately one million per second) that are extremely short (less than a billionth of a second in duration) and that are in a frequency range substantially lower than convention radars. Low frequency pulses are better able to penetrate solid objects. Additionally, MIR radars are extremely selective in their range gating capabilities. It is possible to examine and record only those echoes that could have been generated by an object within a certain range from the radar unit and ignore all others. Due to the high pulse rate and low frequency, echoes from many objects that are lined up in a row may be received, thus allowing the radar to "see behind" objects, detecting other objects that would otherwise be visually hidden.
Global positioning satellite (GPS) systems are known that provide the location of a global positioning receiver by sophisticated triangulation algorithms using data provided by orbiting satellites with a high degree of accuracy. Accuracy, to millimeter tolerances may be obtained by using differential GPS.
Effective means for the digital transmission of data via radio by multiple transmitters operating on a single frequency are known. Various techniques are employed to prevent transmissions from different computing devices using the same frequency from preventing communications. Carrier Sense Multiple Access with Collision Detection (CSMA/CD) is widely employed in both wireless radio applications and in wired computer networks.
Radar devices that will detect, for example, a stud behind a sheet rock wall, are known. These devices do not provide any transmission or storage of the location of the hidden object.
Computer Aided Design (CAD) computer software packages are known that accept as input the coordinates that describe a three-dimensional structure and then generate drawings of that structure.
The Problems
A principal problem solved by this invention is that of capturing "as built" information about buildings or other structures. It also provides a quick and easy way of surveying the internals of walls and the content of rooms and of automatically generating a computer representation of the building.